1. Field of the Invention
The present invention relates to a lens apparatus which can be extended outward in an optical axis direction to perform zoom operation and can be put into a barrel body, and to a camera which has the lens apparatus.
2. Description of Related Art
A conventional camera which has a solid-state image-pickup element and a collapsible lens apparatus with a magnification of approximately two to three times is formed such that a first lens unit closer to an object side is largely moved in an optical axis direction in a WIDE state to provide large spacing between the first lens unit and a second lens unit closer to an image side than the first lens unit. During zooming from the WIDE state to a TELE state, the first lens unit is moved along a convex trajectory toward the image side and the second lens unit is largely moved toward the object side from the WIDE position to reduce the spacing between the first lens unit and the second lens unit.
Such a camera is formed such that the first lens unit and the second lens unit are put (they are collapsed) into a camera body when no image is taken. The camera is disclosed in Japanese Patent No. 3297658.
To achieve the collapsing operation and variable magnification operation of the lens apparatus as described above, barrel members in two stages are used in which the first lens unit is held by the barrel member in the first (foremost) stage and the second lens unit is held by the barrel member in the second stage having a cam. Cams are provided to drive the first lens unit and the second lens unit in response to the collapsing operation and the variable magnification operation of the lens apparatus.
However, when the aforementioned conventional structure is used in a zoom lens apparatus which realizes a change in focal length at a high magnification of three times or more, the moving amount of the first lens unit is increased in a WIDE mode to further increase the spacing between the first lens unit and the second lens unit in the WIDE mode. On the other hand, in a TELE mode, the spacing between the first lens unit and the second lens unit is reduced to the same level as in the aforementioned conventional lens apparatus.
For this reason, when the lens apparatus has barrel members in two stages and the second stage is provided with a cam for driving the first lens unit and the second lens unit to perform the collapsing operation and variable magnification operation as in the conventional lens apparatus, the spacing between the first and second lens units when the lens is collapsed is largely different from the spacing when the variable magnification operation is performed (in the WXDE state). The overall length of the barrel member in the second stage is thus increased in the optical axis direction in order to ensure the moving amounts of the first and second lens units. This presents a problem that the collapsed lens apparatus cannot be put compactly into a camera body to result in an increased size of the camera.